The present invention relates, in general, to an improved surgical biopsy instrument and, more particularly, to a removable firing fork mechanism for use in a surgical biopsy instrument.
The diagnosis and treatment of patients with cancerous tumors, premalignant conditions, and other disorders has long been an area of intense interest in the medical community. Non-invasive methods for examining tissue and, more particularly, breast tissue include palpation, X-ray imaging, MRI imaging, CT imaging, and ultrasound imaging. When a physician suspects that tissue may contain cancerous cells, a biopsy may be done using either an open procedure or in a percutaneous procedure. In an open procedure, a scalpel is used by the surgeon to create an incision to provide direct viewing and access to the tissue mass of interest. The biopsy may then be done by removal of the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). In a percutaneous biopsy, a needle-like instrument is inserted through a very small incision to access the tissue mass of interest and to obtain a tissue sample for examination and analysis. The advantages of the percutaneous method as compared to the open method are significant: less recovery time for the patient, less pain, less surgical time, lower cost, less disruption of associated tissue and nerves and less disfigurement. Percutaneous methods are generally used in combination with imaging devices such as X-ray and ultrasound to allow the surgeon to locate the tissue mass and accurately position the biopsy instrument.
Generally there are two ways to percutaneously obtain a tissue sample from within the body, aspiration or core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into small enough pieces to be withdrawn in a fluid medium. Application is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core biopsy, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors and no single procedure is ideal for all cases.
A number of core biopsy instruments which may be used in combination with imaging devices are known. Spring powered core biopsy devices are described and illustrated in U.S. Pat. Nos. 4,699,154, 4,944,308, and Re. 34,056. Aspiration devices are described and illustrated in U.S. Pat. Nos. 5,492,130; 5,526,821; 5,429,138 and 5,027,827.
U.S. Pat. No. 5,526,822 describes and illustrates an image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument which takes multiple tissue samples without having to re-puncture the tissue for each sample. The physician uses this biopsy instrument to xe2x80x9cactivelyxe2x80x9d capture (using the vacuum) the tissue prior to severing it from the body. This allows the physician to sample tissues of varying hardness. The instrument described in U.S. Pat. No. 5,526,822 may also be used to collect multiple samples in numerous positions about its longitudinal axis without removing the instrument from the body. A further image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument is described in commonly assigned U.S. application Ser. No. 08/825,899, filed on Apr. 2, 1997 and in U.S. Pat. Nos. 6,007,497; 5,649,547; 5,769,086; 5,775,333; and 5,928,164. A handheld image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instrument is described in U.S. Pat. No. 6,086,544 and in U.S. Pat. No. 6,120,462. The instrument described therein moves drive motors and other electronic components into a control unit separate from and remotely located from the biopsy probe. Biopsy probe cutter rotational and translational motion is transferred from the motors in the control unit to the biopsy probe via flexible coaxial cables. This arrangement greatly improves the cleanability of the reusable hardware that remains in close proximity to the biopsy site as well as improves the life and durability of the electric motors and electronic components now remotely located from the biopsy probe. The biopsy instrument described and illustrated in U.S. Pat. No. 6,086,544 and in U.S. Pat. No. 6,120,462 was designed primarily to be a xe2x80x9chand heldxe2x80x9d instrument to be used by the clinician in conjunction with real time ultrasound imaging. Several image-guided, vacuum-assisted, percutaneous, coring, breast biopsy instruments are currently sold by Ethicon Endo-Surgery, Inc. under the Trademark MAMMOTOME(trademark).
The majority of breast biopsies done today, however, utilize an x-ray machine as the imaging modality. Using x-ray requires that the biopsy instrument be affixed to the x-ray machine by some type of bracket arrangement. Since the biopsy instrument is fixed to a portion of the x-ray machine there is now a need for a means to conveniently rotate the biopsy probe once it is advanced into the breast in order to accurately position the vacuum port at the distal end of the probe.
In U.S. Pat. No. 5,649,547 a biopsy device is disclosed which includes a drive assembly containing a stored energy probe xe2x80x9cfiringxe2x80x9d mechanism. This firing mechanism is used by the clinician to rapidly advance the biopsy probe piercing element into the patient during a biopsy procedure, which is necessary to penetrate the dense tissue comprising many lesions. Also disclosed in U.S. Pat. No. 5,649,547 is a xe2x80x9cfiring forkxe2x80x9d, which is the attachment point of the biopsy probe piercing element to the stored energy firing mechanism. The firing fork is permanently affixed to the firing mechanism and is designed to attach to the proximal end of the biopsy probe so that the probe can be readily removed from the firing fork and firing mechanism after the biopsy procedure for disposal. It is important for the firing fork to be maintained perpendicular to base in order to assure that the biopsy probe enters the patient axial to the base and that the biopsy probe and firing fork remain properly coupled when fired into the patient. Any bending of the firing fork support could misalign the probe as it is fired into the patient. In the prior art devices this is accomplished by permanently affixing the firing fork to the firing mechanism.
In actual clinical use, the firing fork is in close proximity to the surgical site. As a result the firing fork is easily contaminated with body fluids and must therefore be thoroughly cleaned and sterilized after each use. In the prior art devices the firing fork is not readily removable from the firing mechanism or the rest of the biopsy device. This means the entire biopsy device must be removed from the x-ray machine so that the firing fork can be cleaned and sterilized.
This can have a negative affect on the efficiency and productivity of a hospital or clinic since significant downtime must be scheduled between patients to allow for the removal of the entire biopsy device for cleaning, or, a second or even third biopsy device must be purchased as backup and maintained ready for consecutive biopsy procedures. Yet another challenge, with respect to the actual cleaning and sterilization process, involves thoroughly cleaning and sterilizing the firing fork portion of the biopsy device while protecting the motors, electronics, and other components within the biopsy device that can be damaged by cleaning solutions and the sterilization process.
It would, therefore, be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, breast biopsy instrument which may be conveniently mounted to an x-ray machine, and incorporate into it a firing fork that is easy to remove and includes a means of maintaining the firing fork perpendicular to the base when the biopsy probe is fired into the patient. It would further be advantageous to design an image-guided, vacuum assisted, percutaneous, coring, breast biopsy instrument which may be conveniently mounted to an x-ray machine which would incorporate a firing fork with a means to maintain the firing fork perpendicular to the base when the biopsy probe is fired into the patient that is easy to remove without the use of special tools.
The present invention is directed to a biopsy instrument including a base assembly including a firing mechanism, a probe assembly detachably mounted to the base assembly and a drive assembly detachably mounted to a portion of the probe assembly. The firing mechanism includes a firing fork assembly moveably attached to a distal end of the base assembly and a drive rod. The firing fork assembly including a firing fork, an inner support rod attached to the firing fork at a distal end thereof and an outer support rod surrounding at least a portion of the inner support rod, the outer support rod being rotatably attached to the inner support rod. The inner support rod including a first attachment mechanism at a distal end of the inner support rod adapted to fixedly attach the inner support rod to the firing fork, a second attachment mechanism at a proximal end of the inner support rod and a third attachment mechanism intermediate the first attachment mechanism and the second attachment mechanism. The drive rod being adapted to move the firing fork wherein the drive rod is slideably attached to the inner support rod by the second attachment mechanism and is fixedly attached to a proximal end of the outer support rod by a fourth attachment mechanism. The probe assembly including a cutter assembly and a piercer assembly detachably mounted on the fork and slideably mounted on the cutter assembly. The drive assembly including a flexible drive shaft operatively connected to the cutter assembly.
The present invention is further directed to a biopsy instrument including a base assembly including a firing mechanism, a probe assembly detachably mounted to the base assembly and a drive assembly detachably mounted to a portion of the probe assembly. The firing mechanism includes a firing fork assembly moveably attached to a distal end of the base assembly and a drive rod. The firing fork assembly including a firing fork, an inner support rod having a threaded distal end, a proximal end and annular groove between the distal end and the proximal end and an outer support rod surrounding at least a portion of the inner support rod, the outer support rod being rotatably attached to the inner support rod at the annular ring. The drive rod is adapted to receive the proximal end of the inner support rod the outer support rod being threaded to the drive rod. The probe assembly including a cutter assembly and a piercer assembly detachably mounted on the fork and slideably mounted on the cutter assembly. The drive assembly being detachably mounted to the cutter assembly, the drive assembly including a flexible drive shaft operatively connected to the cutter assembly.
The present invention further includes a removable fork assembly for use in a medical instrument, the removable fork assembly including a firing fork, an inner support rod having a threaded distal end, a spade connector at a proximal end and annular groove between the distal end and the proximal end and an outer support rod surrounding at least a portion of the inner support rod, the outer support rod being rotatably attached to the inner support rod at the annular ring.